A piezoelectric vibrator has been widely used that includes a base substrate and a lid substrate, both made of glass, anodically bonded in layers with a cavity formed therebetween, and a piezoelectric vibrating piece mounted on the base substrate in a portion inside the cavity. The piezoelectric vibrator of this type has been used for applications such as a clock source, a timing source of control signals or the like, and a reference signal source by being installed in, for example, cellular phones and personal digital assistant units.
In conventional piezoelectric vibrators, the piezoelectric vibrating piece is mounted by connecting and fixing the mount electrodes of the piezoelectric vibrating piece to a conductive adhesive applied on the inner electrodes formed on the base substrate (see, for example, JP-A-2000-124755).
Recently, in order to more reliably mount the piezoelectric vibrating piece inside the cavity, a method for mounting the piezoelectric vibrating piece by a technique known as flip-chip bonding has been proposed in which the mount electrodes of the piezoelectric vibrating piece are connected and fixed to the bumps made of, for example, gold, formed on the inner electrodes formed on the base substrate.